/*
 moxl - Modular XML Library
 Copyright (c) 2007, Malcolm Sparks

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package moxl.xpath;

import moxl.dom.MoxlNode;
import moxl.reader.LocateableReader;
import moxl.reader.XPathExpressionReader;
import moxl.tokenizer.TokenStream;
import moxl.tokenizer.Tokenizer;
import moxl.tokenizer.WhitespaceFilteringTokenStream;
import moxl.xpath.parser.XPathParser;
import moxl.xpath.parser.XPathParserException;
import moxl.xpath.parser.types.Expression;
import moxl.xpath.parser.types.PathExpression;
import moxl.xpath.tokenizer.StartState;

public class XPathHelper
{
	private XPathHelper()
	{
	}

	public static <T extends MoxlNode> XPathParsedQuery<T> compile(String locationPath) throws XPathParserException
	{
		TokenStream tstream = makeTokenStream(locationPath);
		XPathParser parser = new XPathParser();
		PathExpression path = parser.parseLocationPathFromStream(tstream);
		return new XPathParsedQuery<T>(path);
	}

	public static Expression compileExpression(String expr) throws XPathParserException
	{
		TokenStream tstream = makeTokenStream(expr);
		XPathParser parser = new XPathParser();
		return parser.parseExpressionFromStream(tstream);
	}

	private static TokenStream makeTokenStream(String locationPath)
	{
		LocateableReader reader = new XPathExpressionReader(locationPath);
		Tokenizer toker = new Tokenizer(reader, StartState.getInstance());
		return new WhitespaceFilteringTokenStream(toker);
	}

}
